With the increase in size of the liquid crystal display (LCD), the RC delay of various signal lines in the LCD may become more apparent, which will result in less efficient pixel charge and eventually affect the display quality of the LCD.
In order to reduce the stray capacitance between the signal lines and lower the RC delay, the current solution is adding one overcoat layer having a huge thickness after the second layer of metal (i.e. the metal for manufacturing the source and drain) of the array substrate is manufactured. The overcoat layer may increase the distance from the second layer of metal to the pixel electrode and the public electrode, thus can be used to reduce the stray capacitance.
In addition, in order to save the cost, the overcoat layer and the passivation layer are manufactured at the same time, also, a relatively large opening area is manufactured at the edge area of the array substrate so as to expose the bonding pad structure. However, since the thickness of the manufactured overcoat layer is relatively large (normally being 1.5 μm to 3.0 μm), the conductive layer can be easily broken when being manufactured on the bonding pad structure and the overcoat layer.
In addition, the bonding pad structure is electrically connected to, for example, the chip on the film (COF) through the anisotropic conductive film (ACF), and the conductive particles are scattered in the ACF. When the ACF is pressed, the conductive particles will move toward the periphery of the bonding pad structure, wherein a part of the conductive particles will reach the bottom of the overcoat layer; since the thickness of the overcoat layer is relatively large, the part of conductive particles may hardly go over the overcoat layer so as to gather at the bottom part of the overcoat layer, hence causing the short circuit between different signal lines (such as the scan line and the data line).